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问题 选择题

如图所示，沿光滑水平面运动的小滑块，当它冲上光滑的斜面时，它受到的力是

[ ]

A．重力、弹力、上冲力

B．重力、弹力

C．重力、弹力、下滑力

D．重力、弹力、上冲力、下滑力

答案

答案：B

单项选择题

The nurse preparing to give a child an intramuscular injection chooses to give the injection into the gluteal muscle. The site is acceptable because which of the following reasons

A. The child has been walking for 1 year.
B. The child has small deltoid muscles.
C. The child is older than 2 years.
D. The child weighs more than 25 pounds.
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单项选择题

有关主起落架收放作动筒的描述错误的是（）

A、放下起落架后还起到侧撑杆的作用

B、放下后靠内部锁锁住

C、收上后靠内部锁锁住
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